SCF Reference Manual for the Storage Subsystem (G06.28+, H06.05+, J06.03+)

• The primary disk and mirror disk of a mirrored pair of M8xxx disks must be in different
FCDMs, connected to a different pair of Fibre Channel loops.
• On NonStop S-series servers the system disk and its mirror cannot be M8xxx Fibre Channel
disks.
• During normal operations, a disk should be mirrored with another disk of the same type. If
you revive an IOMF disk to a newer type of disk, the system will use a migratory revive that
will down the source drive after the revive is complete. For information about the migratory
revive operation, ask your service provider to refer to the Modular I/O Installation and
Configuration Guide.
• SCF requires that you specify a primary and a backup path when configuring an M8xxx
disk.
• AUTOCONFIGURE is not recommended for M8xxx disks. Confirm that this attribute is OFF
before adding M8xxx disks.
• New M8xxx disks that are being used for the first time must be initialized after they have
been added.
Considerations for ESS Disks
• The primary and mirror logical devices (LDEVs) in the ESS must be in different physical array
groups.
• The primary LUN on the primary and backup paths must be the same.
• The mirror LUN on the mirror and mirror backup paths must be the same.
• For ESS disks connected to Storage CLIMs, ESS or XP LUN 0 must be defined.
For more ESS configuration information, see the Modular I/O Installation Guide or the NonStop
planning guide for your particular system.
Considerations for CLIM-Attached Disks
• The primary and mirror disks must be in different disk enclosures. It is better if they are on
different Storage CLIM pairs.
System Disk Configuration
When you configure the system disk, these restrictions exist:
• You cannot use SCF to configure the system disk. The system generation program configures
the system disk. If the system disk is configured improperly, the system halts during system
load, and you must use the system generation program to recover.
• You can specify an alternate system disk and perform a system load from it to create an
alternate system configuration. For more information, see the NonStop S-Series Hardware
Installation and FastPath Guide.
• For NonStop S-series systems, enclosure interleaving is not supported for the system disks.
Both halves of the system disk must be in enclosure 1.
• Beginning with G06.06, on NonStop S-series systems, the system disk can reside in other
slots in group 01 besides 11 and 12. For more information, refer to the NonStop S-Series
Planning and Configuration Guide.
72 Configuring Disks